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Slide 2

The Early Periodic Table JohannDobereiner John Dalton John Newlands Dmitri Mendeleev19th Century 19th Century 19th Century 19th Century…read more

Slide 3

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JohannDobereinerIn 1829, he put some ofthe elements into groupsof three (known as triads).The elements in his triadshad similar chemical andphysical properties.…read more

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During the 19th Century, new elements we being discovered almost every year. Chemists were trying to find patterns in the properties and behaviour of the elements, as this would allowthem to acquire more knowledge about chemistry. One of the first suggestions came from JohnDalton who arranged the elements in order of their masses. John Dalton…read more

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In 1864, John Newlands developed on Dalton's ideas using a `law of octaves' (octave means eight). After arranging all the know elements in order of mass, he noticed that every eighth element had similar properties. However, thisJohn Newlands pattern fell apart when he reached calcium. Other scientists made fun of his ideas and wouldn't accept them.…read more

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Dmitri MendeleevIn 1869, Dmitri Mendeleev made the breakthrough thatwould change chemistry forever. Mendeleev arrangedthe 50 known elements in a table, and placed them inorder of their atomic weights. He arranged them in away so that he could see a regular pattern in theirproperties. What made his idea revolutionary was thathe thought to put gaps for undiscovered elements.Using his table, he was able to predict what theproperties of missing elements could be. A few yearslater, elements were discovered that closely matched…read more